JP2011258747A - Solar cell module - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve the problem that in a solar cell module configured by a plurality of solar cells connected in series, cracking and warpage of the solar cells and detachment of the electrodes are likely to occur due to residue stress caused by heating during connection of the front surface electrode of each solar cell and the back surface electrode of the adjacent solar cell by soldering a belt-shaped tab wire.SOLUTION: In two adjacent solar cells, a front surface side tab wire of one solar cell is soldered to a back surface side tab wire which extends to the back surface side of the other solar cell and which is connected to a back side electrode, and a plurality of such solar cells are connected in series. The width of the tip section of one or both of the surface side tab wire and the back surface side tab wire at the bonded part of the front surface side tab wire and the back surface side tab wire are smaller than the widths of other sections than the tip section.

Description

  The present invention relates to a solar battery module configured by connecting electrodes of adjacent solar battery cells in series with tab wires.

As a conventional solar cell module, a plurality of solar cells having a surface electrode on the front surface and a back electrode on the back surface are arranged side by side, and one solar cell is used to connect the plurality of solar cells in series. There is known a solar cell module having a configuration in which a surface electrode of a cell and a back electrode of another adjacent solar cell are connected by a strip-shaped tab line and this is repeated in order.

The strip-shaped tab wire is generally used by soldering the entire surface of a highly conductive metal such as copper foil, and is arranged to extend from the surface electrode of the solar cell to the back electrode of the adjacent solar cell. And connected to the front electrode and the back electrode. The tab wire is connected to each electrode by arranging the tab wire on the elongated electrode from the end to the end of the front and back surfaces of the solar cell and heating it to melt the solder. This is performed by pressing the wire and the solar battery cell and soldering them.
By the way, since the solar cell that is a semiconductor (silicon) and the tab wire that is a metal have different linear expansion coefficients, residual stress is generated in the solar cell due to a difference in thermal shrinkage at the time of solder connection. Warpage, cracking, and electrode peeling were likely to occur. That is, the solar battery cells and the tab wires are soldered in an expanded state due to heating during solder joining, and the tab wire having a large linear expansion coefficient tends to contract more than the solar cells when cooled after that. The solar battery cell may be warped by being pulled by the tab wire, or may be cracked or peeled off.
Patent Document 1 discloses a configuration in which the residual stress at the time of solder bonding is reduced by reducing the 0.2% proof stress value of a copper wire to 90 MPa or less. Further, Patent Document 2 is connected to the surface side as means for eliminating cell cracking due to residual stress that occurs when the cross section of the tab wire is increased in order to suppress an increase in series resistance that occurs with an increase in cell area. A configuration is disclosed in which a tab line connected to the tab line and the back side is provided separately, and the separately provided front side tab line and back side tab line are connected.

JP 2006-54355 A (page 5) JP 2002-359388 A (page 3-4, FIG. 2)

However, in order to reduce the residual stress at the time of soldering by means of Patent Document 1, it is necessary to create a copper wire having a low 0.2% proof stress value. The cost of the solar cell module is increased because the cost is higher than that of the copper wire.
Moreover, even if the residual stress generated by the means of Patent Document 2 is suppressed to one cell, the cross-sectional area of the tab line overlaps with the part where the front side tab line and the back side tab line are joined. Therefore, there is a problem that plastic deformation is difficult to occur, and a residual stress generation value at a joint portion increases, and cell cracks, warpage, and electrode peeling in the vicinity thereof easily occur.

This invention is made | formed in view of the above, Comprising: Without using a copper wire with a low 0.2% yield strength as a tab wire which connects a photovoltaic cell, a tab wire is made into the surface side and a back surface side. In the solar cell module provided separately, the residual stress at the junction between the front-side tab wire and the back-side tab wire is reduced, and the occurrence of cell cracking, warping or electrode peeling of the solar cell is suppressed. An object is to obtain an inexpensive solar cell module with a good yield.

In the solar cell module according to the present invention, a plurality of solar cells having a surface electrode on the front surface and a back electrode on the back surface, a strip-shaped surface-side tab wire solder-bonded to the surface electrode of the solar cell, and the solar cell A strip-like backside tab line soldered to the backside electrode of the cell, and the surface side tab line of one of the adjacent solar cells is on the backside of the other solar cell A plurality of solar cells are connected in series by soldering to the back-side tab wire connected to the extended back-side electrode, and the end in the longitudinal direction of the front-side tab line or the end in the longitudinal direction of the back-side tab wire The width of is smaller than the width other than the end portion.

According to this invention, by reducing the width of the end portion in the longitudinal direction of the front surface side tab line or the end portion in the longitudinal direction of the back surface side tab line with respect to the width other than the end portion, The tab line cross-sectional area of the joint between the solar cell electrode and the tab wire can be reduced to facilitate plastic deformation, and the residual stress generated in the solar cell after soldering can be reduced. Thereby, even if it does not reduce the proof stress value of a tab wire, the cell crack of the photovoltaic cell resulting from the thermal stress at the time of connection of a tab wire and a photovoltaic cell, curvature, and electrode peeling can be suppressed.

It is the front view seen from the surface side of the solar cell module which shows Embodiment 1 of this invention. It is a fragmentary sectional view of the solar cell module which shows Embodiment 1 of this invention. It is sectional drawing which shows the connection of the two adjacent photovoltaic cell of the solar cell module which shows Embodiment 1 of this invention. It is a front view (surface side) which shows the connection of the two adjacent photovoltaic cell of the solar cell module which shows Embodiment 1 of this invention. It is a front view (back side) which shows connection of two adjacent photovoltaic cells of the solar cell module which shows Embodiment 1 of this invention. It is a fragmentary figure (back side) which shows the tab line connection part in two adjacent photovoltaic cells of a solar cell module which shows Embodiment 1 of the present invention. It is a front view (back surface side) which shows the other example of the connection of the two adjacent photovoltaic cell of the solar cell module which shows Embodiment 1 of this invention. It is another partial view (back surface side) which shows the tab wire connection part in the two adjacent photovoltaic cell of the solar cell module which shows Embodiment 1 of this invention. It is a front view (back side) which shows another example of the connection of two adjacent photovoltaic cells of the solar cell module which shows Embodiment 1 of this invention. It is a front view (back surface side) which shows the further another example of the connection of the two adjacent photovoltaic cell of the solar cell module which shows Embodiment 1 of this invention. It is a front view (surface side) which shows the connection of the two adjacent photovoltaic cell of the solar cell module which shows Embodiment 2 of this invention. It is a front view (back surface side) which shows the other example of the connection of the two adjacent photovoltaic cell of the solar cell module which shows Embodiment 2 of this invention. It is a front view (back surface side) which shows the connection of two adjacent photovoltaic cells of the solar cell module which shows Embodiment 3 of this invention.

Embodiment 1 FIG.
Embodiments of a solar cell module according to the present invention will be described below in detail with reference to the drawings.
FIG. 1 is a front view of the entire solar cell module according to Embodiment 1 of the present invention as viewed from the surface side. In FIG. 1, a solar cell module 1 is made by resin-sealing a plurality of solar cells 2 arranged vertically and horizontally, covering the light receiving surface side with a translucent surface cover material 3, and the back surface side with a back surface cover material (FIG. 1). And a frame member 6 that surrounds the outer edge of the solar cell panel 5 over the entire circumference.
The plurality of solar cells 2 are connected in series in the X direction in the drawing, which is the first direction, by a front surface side tab wire 4 and a back surface side tab wire (not shown). However, in the edge part of the solar cell panel 5, there is also a location connected in the Y direction. In addition, as the front surface side tab wire and the back surface side tab wire, a band-shaped copper foil coated with solder is used.
The frame member 6 is produced by extrusion molding of aluminum or the like, and covers the outer edge portion of the solar cell panel 5 over the entire circumference with a U-shaped portion having a U-shaped cross section. The frame member 6 is fixed to the solar cell panel 5 through a butyl-based sealing material or a silicon-based adhesive, and reinforces the solar cell panel 5 and also attaches the solar cell panel 5 to a building such as a house or a building. It has a role to attach to a gantry provided on the ground or structure.

2 is a cross-sectional view of the portion indicated by BB of the solar cell panel 5 in the region A of FIG. In FIG. 2, the solar cell panel 5 connects the translucent surface cover material 3, the plurality of solar cells 2a, 2b, and these solar cells 2a, 2b in series from the light receiving surface side (front surface side). A cell arrangement layer 9 in which the front side tab wires 4a and 4b and the back side tab wires 7a and 7b are sealed with a resin 8 such as EVA (ethylene vinyl acetate), PET (polyethylene terephthalate), PVF (polyvinyl fluoride), etc. The back sheet 10 (back cover material) having excellent weather resistance is laminated.
FIG. 3 shows the solar cell 2a, 2b and the front surface side tab wires 4a, 4b and the back surface side tab wires 7a, 7b which are electrically connected to the stacked structure shown in FIG. FIG.

FIG. 4 is a front view of the solar cells 2a and 2b in the region A shown in FIG. 1 as viewed from the surface side that is the light receiving surface side. FIG. 5 is a front view of the connection of solar cells in the region A shown in FIG. 1 as seen from the back side (the view of FIG. 4 seen from the back side).

Next, a solar cell will be described in detail with reference to FIGS. 3, 4, and 5.
Solar cells 2a and 2b are configured as follows using p-type silicon having a thickness of about 150 to 300 μm as a substrate. An n-type diffusion layer (not shown) is formed on the surface side of the p-type silicon substrate 11 to be a p-type layer, and an antireflection film (not shown) for preventing reflection of incident light and improving conversion efficiency. (Not shown) is provided by surface treatment, and serves as a light receiving surface of the solar battery cell. Further, a p ⁺ layer (not shown) containing a high concentration impurity is formed on the back surface side of the p-type silicon substrate, and the back surface is made of aluminum on almost the entire back surface for the purpose of reflecting incident light and taking out electric power. A collecting electrode 12 is provided.
The light receiving surface is provided with surface grid electrodes 13a and 13b and surface bus electrodes 14a and 14b as surface electrodes for extracting electric energy converted from incident light. As shown in FIG. 4, the surface bus electrodes 14a and 14b are formed along a first direction which is a connection direction between adjacent solar cells, and the surface grid electrodes 13a and 13b are formed by the surface bus electrodes 14a, A plurality of lines are formed in parallel to each other perpendicular to 14b. The surface grid electrodes 13a and 13b are formed over the entire light receiving surface (surface) in order to take out the electric power generated on the light receiving surface without waste.

The surface grid electrodes 13a and 13b and the surface bus electrodes 14a and 14b are formed as follows. A plurality of silver pastes having a width of about 100 μm are linearly applied to the surface of the solar battery cell at intervals of about 2 mm, and the solar cells are orthogonal to the silver paste having a width of about 2 mm. It is formed by coating each of the cells at positions near a quarter of the cell width from both ends of the cell and baking these silver pastes. The portions of the silver paste having a width of 100 μm applied in parallel become the surface grid electrodes 13a and 13b, and the portions of the silver paste having a width of 2 mm applied so as to be orthogonal to the surface grid electrodes 13a and 13b are the surface bus electrodes 14a, 14b. The surface grid electrodes 13a and 13b and the surface bus electrodes 14a and 14b intersect at right angles and are electrically connected.

Further, in order to take out the electric energy collected by the back surface collecting electrode 12 provided on almost the entire back surface, the back surface bus electrodes 15a and 15b made of silver are in the connecting direction between adjacent solar cells. It is formed along the first direction.

In the solar cell configured as described above, sunlight is irradiated from the light receiving surface side (antireflection film side) of the solar cell, and an internal pn junction surface (a junction surface between the p-type layer and the n-type diffusion layer). ), The holes and electrons combined at the pn junction surface are separated. The separated electrons move toward the n-type diffusion layer. On the other hand, the separated holes move toward the p ⁺ layer. As a result, a potential difference is generated between the n-type diffusion layer and the p ⁺ layer so that the potential of the p ⁺ layer becomes high. As a result, the front electrode connected to the n-type diffusion layer is a negative electrode, the back electrode connected to the p ⁺ layer is a positive electrode, and if an external circuit (not shown) is connected, current flows, The operation is shown.
Although the output voltage of one solar battery cell is small, in the solar battery module, a plurality of solar battery cells are connected in series to increase the voltage to be easy to use.

The solar cells are connected in series with each other in the plurality of solar cells arranged in the first direction. The surface electrode (surface bus electrode 14a) of one solar cell 2a and the other solar cells adjacent thereto. This is done by electrically connecting the 2b back electrode (back bus electrode 15b) with a strip-shaped tab wire.

Specifically, in the present embodiment, the tab lines are divided into front side tab lines 4a and 4b and back side tab lines 7a and 7b. Of the two tab lines, the surface side tab lines 4a and 4b extend on the surface bus electrodes 14a and 14b, and are soldered (mechanically and electrically connected) to the surface bus electrodes 14a and 14b. Since the length of the surface side tab wires 4a and 4b is longer than the length of the surface bus electrodes 14a and 14b, one end of the surface bus electrodes 14a and 14b and one end of the surface side tab wires 4a and 4b are combined. When placed and soldered, the other ends of the surface-side tab wires 4a and 4b protrude from the other ends of the surface bus electrodes 14a and 14b as extra lengths. On the other hand, the back-side tab wires 7a and 7b extend on the back-side bus electrodes 15a and 15b, and are solder-joined (mechanically and electrically connected) to the back-side bus electrodes 15a and 15b. And in order to connect the photovoltaic cell 2a and the adjacent photovoltaic cell 2b in series, the surface side tab wire 4a of the photovoltaic cell 2a and the back surface side tab wire 7b of the photovoltaic cell 2b are solder-joined. That is, the end portion of the front side tab wire 4a, that is, the extra length, digs into the back side of the adjacent solar battery cell 2b and is soldered to the back side tab wire 7b soldered onto the back side bus electrode 15b. Is done. Here, only the connection between two adjacent solar cells 2a and 2b has been described, but actually, the same connection is repeated and a plurality of solar cells 2 are connected in series.
In FIG. 5, the widths of the front-side tab lines 4a and 4b are smaller than the widths of the back-side tab lines 7a and 7b. However, the widths of the tab lines are the same. It's okay. The same applies to FIG. 6 and subsequent figures.

Specifically, the connection between the solar battery cell and the tab wire is performed as follows.
First, the front side tab wire 4a is disposed on the front surface bus electrode 14a of the solar battery cell 2a, and the rear surface side tab wire 7a is disposed on the rear surface bus electrode 15a. Press against the solar cell. Since the tab wire is covered with solder, the solder is melted by heating, and the tab wire and the bus electrode are soldered by pressing in this state. Next, the solar cells 2a and 2b that will be adjacent to each other in the solar cell module 1 are arranged, and the end portion (extra length) of the surface-side tab wire 4a of one solar cell 2a is changed to that of the other solar cell 2b. It rubs over to the back side and overlaps with the end of the back side tab wire 7b and presses and solders while heating.
In addition, you may implement simultaneously the connection of each electrode of said photovoltaic cell and each tab wire, and the connection of a surface side tab wire and a back surface side tab wire.

Thus, the solar cell module 1 in which a plurality of solar cells 2 are connected in series is configured, and the output voltage is a value obtained by connecting a plurality of solar cells 2 in series.

And in this Embodiment, the width | variety of the edge part of the side connected to the back surface side tab wire 7b of the adjacent photovoltaic cell 2b of the surface side tab wire 4a of the photovoltaic cell 2a is the surface side tab wire 4a. It is narrower than the width of the portion other than the end. For example, as shown in FIG. 5, the front-end | tip of the surface side tab wire 4a is sharpened acutely, and the sharp part is smaller than 60 degrees.
The shape dimension of the edge part of the surface side tab wire 4a in the connection part of the surface side tab wire 4a and the back surface side tab wire 7b is demonstrated using FIG. As for the conventional surface side tab line and the back side tab line, those whose end portions are cut at right angles to the longitudinal direction of the tab line, that is, rectangular ones are used. Therefore, the overlapping part of the front surface side tab line and the back surface side tab line was also rectangular. In such a conventional tab line connection, when the tab line width is W, the length of the overlapping portion of the front side tab line and the back side tab line is generally about W to 5W. This ensures the connection strength of the connection part between the front-side tab line and the back-side tab line, and suppresses the resistance value at the connection part between the front-side tab line and the back-side tab line to be small (reduction of power loss at the connection part). In addition, when the length of the overlapping portion is too long, the dimension is selected in consideration of the cost increase due to an increase in the tab line length. In the present embodiment, considering the above reasons, desired values of each dimension are selected as follows.
First, from the viewpoint of connection strength and resistance suppression, the area (S) of the overlapping portion between the front surface side tab wire 4a and the rear surface side tab wire 7b is preferably equal to or larger than that of the conventional one. Further, in the front side tab line 4a overlapping the back side tab line 7b, the length (L2) of the portion where the tab line width is W is preferably 0 or less and about 0.5 W or less. This is because it is assumed that if L2 is long, it will be close to the conventional connection, and the residual stress at that portion cannot be relaxed. Furthermore, from the viewpoint of suppressing an increase in material cost, it is desirable that the length (L1) of the overlapping portion between the front surface side tab line 4a and the rear surface side tab line 7b does not increase from the conventional value.
As described above, when L2 = 0 and S = W ^ 2 (that is, L1 = W) as an example of the dimension of the connecting portion between the front surface side tab wire 4a and the rear surface side tab wire 7b, the acute angle of the front end of the front surface side tab wire 4a The angle θ in the shape is θ = 53 °.

When the surface-side tab wire 4a has such an end shape, the width (W1 in FIG. 5) of the end of the surface-side tab wire 4a on the side connected to the back-side tab wire 7b is the surface-side tab wire 4a. Since the width (W1 <W) of the portion other than the end portion of the joint portion becomes narrower (W1 <W), the cross-sectional area of the joint portion becomes smaller than when the tab lines having the same width are connected. A portion having a small cross-sectional area is easily plastically deformed when the same force is applied. Therefore, when soldering between the tab wire and the electrode and the tab wire, when subjected to thermal stress caused by the difference in the linear expansion coefficient between the silicon substrate of the solar cell material and the copper of the tab wire material, the tab wire bonding The tab line portion where the cross-sectional area of the portion is small is more easily plastically deformed. Therefore, the residual stress remaining in the solar cell is relaxed by plastically deforming a small portion of the cross-sectional area of the tab wire with respect to the force of thermal contraction when the temperature of the solar cell decreases after soldering, Cell cracks, warpage, tab line peeling, etc. are unlikely to occur.
The thermal stress generated by the difference in linear expansion coefficient between the silicon of the solar cell material and the copper of the tab wire material is accumulated as it moves away from the center of the tab wire in the longitudinal direction, so that it is close to the cell edge. Residual stress tends to increase most at the location. In the present embodiment, plastic deformation is easily performed at the joint between the front-side tab line and the back-side tab line connected at the cell end, and therefore effective in reducing residual stress.

In the solar cell module 1 having such a configuration, when using a copper wire with reduced proof stress as a tab wire for connecting solar cells, and soldering the front side tab wire and the back side tab wire together It is possible to reduce the residual stress generated at the joint portion, and it is possible to suppress the deterioration of the yield due to cell cracking, warpage, peeling of the tab wire, and the like, and the decrease in the output of the solar cell. Therefore, the solar cell module 1 is inexpensive and highly reliable. Can be provided.

In addition, as shown in FIG. 7, even if it is the structure which made the edge part shape of the back surface side tab wire 7b of the side connected with the surface side tab wire 4a into the acute angle shape smaller than 60 degrees, the surface side tab wire 4a and the back surface side tab Since the cross-sectional area of the joint with the wire 7b is reduced and plastic deformation is likely to occur, it is possible to reduce the residual stress generated during solder joining, and the same effect as described above can be obtained.
Further, at the joint portion between the front surface side tab wire 4a and the rear surface side tab wire 7b, both the end portion shape of the front surface side tab wire 4a and the end portion shape of the rear surface side tab wire 7b are formed into acute angles smaller than 60 °. By doing so, since the portion where the cross-sectional area of the joint between the front surface side tab wire 4a and the back surface side tab wire 7b becomes smaller increases, it becomes easier to be plastically deformed, so it becomes possible to reduce the residual stress generated during solder joint. Thus, the same effect as described above can be obtained.

In the above description, the shape of the end portion of the front surface side tab line or the back surface side tab wire is an acute angle shape smaller than 60 °, but the tip portion may be an arc shape. Specifically, as shown in FIG. 8, the end portion of the acute angle shape smaller than 60 ° is rounded. The form having an arc shape at the tip portion has an advantage that it can be manufactured without damaging the back sheet 10 due to deformation of the sharp portion of the tip which is a concern in the case of an acute angle shape.

In addition, since the end portion of the front-side tab line or the back-side tab line has an effect by taking a shape smaller than the tab line width, it may have a plurality of acute-angle shapes as shown in FIG. In this case, as described above, in order to keep the connection strength and the resistance equal to or higher than those of the conventional shape, it is desirable that the area of the overlapping portion between the front surface side tab line and the rear surface side tab line is equal to or higher than that of the conventional shape. At that time, for example, when the number of acute-angled shapes is two, it is preferable to select angles smaller than 30 ° as the angles θ of the acute-angled tips. Further, the end portion may have a plurality of arc shapes.

In FIG. 10, at the joint portion between the front surface side tab wire 4a and the back surface side tab wire 7b, the end surface shape of the front surface side tab wire 4a is an acute angle shape smaller than 60 °, and the back surface side tab wire 7b has a plurality of end shape shapes. An example of an acute-angle shape (for example, two acute-angle shapes whose end portions are smaller than 30 °) is shown. Since the portion where the joint cross-sectional area between the front surface side tab wire 4a and the back surface side tab wire 7b becomes small increases, plastic deformation is further facilitated, and thus the same effect as described above can be obtained.

Embodiment 2. FIG.
FIG. 11: is a front view (surface side) which shows the connection of two adjacent photovoltaic cells of the solar cell module which shows Embodiment 2 of this invention.
In FIG. 11, the width | variety of the edge part of the side which is not connected with the back surface side tab wire 7b of the surface side tab wire 4a is narrowed. Specifically, it was an acute angle shape smaller than 60 °.
As described above, since the thermal stress caused by the difference in linear expansion coefficient between the silicon of the solar cell material and the copper of the tab wire material is accumulated as it moves away from the longitudinal center of the tab wire to the end, Residual stress tends to increase most at locations close to the part. Therefore, not only the junction between the front-side tab wire 4a and the back-side tab wire 7b as shown in the first embodiment, but also by reducing the width of the tab line end connected to the electrode at the cell end. The effect of reducing the residual stress at the cell edge can be obtained. That is, if the width of the end portion of the front surface side tab wire 4a on the side not connected to the back surface side tab wire 7b is made narrower at the joint portion between the front surface side tab wire 4a and the front surface bus electrode 14a, the end portion is at the time of soldering. Since plastic deformation is likely to occur and the residual stress at that part can be reduced, it is possible to suppress the deterioration of yield due to cell cracking, warpage, peeling of the tab wire, etc. and the decrease in output of the solar cell, so it is inexpensive and highly reliable. The solar cell module 1 can be provided.
However, if the acute angle of the end portion is made extremely small, the end portion of the surface-side tab wire 4a becomes narrower and the portion becomes longer, so that the surface bus electrode 14a and the surface-side tab wire 4a Therefore, for example, it is desirable to suppress L3 <5W. For this purpose, it is desirable that the acute angle θ of the end portion is, for example, 10 ° or more.
As shown in FIG. 12, the same effect can be obtained even if the end portion of the back surface side tab wire 7b that is not connected to the front surface side tab wire 4a has an acute angle shape smaller than 60 °.
In the present embodiment, the effect is obtained by taking a shape in which the widths of the end portions of the front-side tab lines 4a and 4b or the back-side tab lines 7a and 7b are smaller than the entire tab line width. You may consist of shape (For example, two acute angle shapes whose angle of a front-end | tip part is smaller than 30 degrees). Furthermore, the tip may be arcuate or may be arcuate.

Embodiment 3 FIG.
FIG. 13: is a front view (back surface side) which shows the connection of two adjacent photovoltaic cells of the solar cell module which shows Embodiment 3 of this invention.
In FIG. 13, the end portions of the back surface side tab wires 7a, 7b on the side connected to the front surface side tab wires 4a, 4b have two acute angles with the tip portion angle smaller than 30 °, and the front surface side tab wires 4a The tips of the back-side tab wires 7a and 7b on the side not connected to 4b have an acute angle smaller than 60 °. In addition, both end shapes of this back surface side tab line are shapes which become a pair, and can cut and produce one tab line in a dogleg shape. Therefore, in addition to the effects of suppressing cell cracking, warpage, tab line peeling, etc., by reducing residual stress that is easily plastically deformed, the shape can be formed by cutting the tab line once with a mold, There is also an effect that costs due to processing can be suppressed.
The back-side tab lines 7a and 7b on the side connected to the front-side tab lines 4a and 4b have an acute end shape smaller than 60 ° and the back-side tabs on the side not connected to the front-side tab lines 4a and 4b. The same applies to the shape of the ends of the lines 7a and 7b, which are two acute angles smaller than 30 °.
Further, the same effect can be obtained when both end shapes of the surface-side tab line are formed as an acute angle shape smaller than 60 ° and two acute angle shapes smaller than 30 °.

DESCRIPTION OF SYMBOLS 1 Solar cell module 2a Solar cell 2b Solar cell 4a Surface side tab wire 4b Surface side tab wire 7a Back surface side tab wire 7b Back surface side tab wire 14a Surface bus electrode (surface electrode)
14b Surface bus electrode (surface electrode)
15a Back bus electrode (back electrode)
15b Backside bus electrode (backside electrode)

Claims (6)

A plurality of solar cells having a surface electrode on the front surface and a back electrode on the back surface;
A strip-shaped surface-side tab wire solder-bonded to the surface electrode of the solar battery cell,
A strip-shaped backside tab wire solder-bonded to the backside electrode of the solar cell,
Of the plurality of adjacent solar cells, the front side tab line of one solar cell is soldered to the back side tab line connected to the back electrode extending to the back side of the other solar cell. The plurality of solar cells are connected in series,
The solar cell module, wherein a width of an end portion in the longitudinal direction of the front surface side tab line or an end portion in the longitudinal direction of the back surface side tab line is smaller than a width other than the end portion. 2. The solar cell module according to claim 1, wherein an end portion in the longitudinal direction of the front surface side tab line or an end portion in the longitudinal direction of the back surface side tab line has an acute angle shape smaller than 60 °. 2. The solar cell module according to claim 1, wherein an end portion in the longitudinal direction of the front surface side tab line or an end portion in the longitudinal direction of the back surface side tab line has an arcuate tip shape. The width of one or both of the end of the front-side tab line and the end of the back-side tab line in the solder joint between the front-side tab line and the back-side tab line is a width other than the end. The solar cell module according to claim 1, wherein the solar cell module is small. Either one or both of the end of the front-side tab line and the end of the back-side tab line in the solder joint between the front-side tab line and the back-side tab line have an acute shape smaller than 60 °. The solar cell module according to claim 2, wherein One or both of an end portion of the surface-side tab line and an end portion of the back-side tab line in the solder joint between the front-side tab line and the back-side tab line have an arcuate tip shape. The solar cell module according to claim 3.

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